DYNACOLL® The label makes a difference DYNACOLL® EP 413.10 and EP 415.10 R eactive hotmelts (RHM) typically contain unreacted monomeric Methylene diphenyl diisocyanate (MDI), which can limit their application. Therefore, one of the major challenges is to reduce the monomer content while, at the same time, maintaining the performance of polyurethane (PUR) formulations when using standard polyesters. Lowering the OH number of existing polyesters increases the viscosity significantly, thus leading to poor RHM storage stability. Evonik has developed two amorphous polyesters that enable RHM producers to reduce the monomeric MDI content to weight values lower than 1% (R40 / H351 free labelling) and balance it with the performance of the PUR formulation. The new amorphous polyesters have a higher molecular weight and lower OH number, but sim- ilar viscosity levels when compared to standard amorphous grades. e a s i e r & s a f e r Low emission polyesters DYNACOLL® 7310 emissions from non-metallic materials; the limit values for the VOC and FOG are, respectively, 100 µg/g and 250 µg/g. R eactive hotmelts (RHM) formulations are based on a modular system composed of amorphous, liquid and crystalline polyesters that enables to tailor the adhesive to different performance specifica- tions. The automotive industry, as a main application area, has spe- cific requirements that need to be considered. Automobiles are sunlight often exposed increasing the temperatures inside the car. Conse- quently, the adhesives have to be resistant to high temperatures. However, at high temperatures vol- atile and semi-volatile compounds (VOC/FOG) are emitted and accu- mulated in the car interior. These compounds have an adverse effect on the air quality, as well as, in the comfort and health of the drivers and passengers. For these and other reasons, the significantly to The analysis of the VOC and FOG values on the cured PUR hotmelts, based on conventional polyesters polyols, shows that amorphous and liquid polyesters can fulfill the limit values in certain combinations. Whereas, crystalline polyesters cannot because the emissions are very high. As crystalline polyesters are important building blocks for the formulation of reactive hotmelts, Evonik have researched and success- fully found low VOC/FOG crystal- line polyesters. DYNACOLL® 7310 is a commercial example of an alternative solution to reduce the emissions of RHM in automotive applications. Does it sound interesting? Contact us to know more. demands of the automotive industry are increasing. Although RHM con- tinue to be the preferred option for applications like door panel lamina- tion, headliner production, mirror bonding and others, the require- ments are becoming stricter. The limit values apply, not only to the complete system but also, to the individual components and the adhesive. The VDA 278 is the ana- lytic method used to determine ADHESIVES The Adhesives Journal of Evonik Industries | 5